Observation of synchronized atomic motions in the field ion microscope

For over half a century, the field ion microscope (FIM) has been used to visualize atomic structures at the apex of a sharpened needle by way of the ion beams which are created at the most protruding atoms. In this paper we used a conventional FIM to study the emission characteristics of the neon ion beams produced within the FIM. The neon emission pattern is observed to be relatively short lived and subject to temporal and angular fluctuations. The nature of these fluctuations is complex, often with different parts of the emission pattern changing in a synchronized fashion over timescales spanning from milliseconds to a few tens of seconds. In this paper, we characterize the observed instability of the neon emission. We also offer a simple model of adsorbed atom mobility that explains much of these observations. And finally, we present a method by which the stability can be greatly improved so that the produced neon beam can be used effectively for nanomachining applications.